Four groups of noinfected rats, 12 in each group, were injected either intraperitoneally or in salivary glands with either formal in killed Actinomyces viscosus plus Freunds adjuvant or just Freunds adjuvant. The procedure was repeated twice in 14 day intervals. The animals were than grouped so that each cage contained one immunized animal, one sham immunized animal and a third animal which had previously been infected with Actinomyces viscosus (T-6). The rate of implantation in the non-infected animals will be monitored and the level of antibodies against T-6 in serum and saliva will be determined.